1. Field of the Invention
This invention relates in general to thin film electromagnetic flying head assemblies and methods for making same, and more particularly to an enhanced silicon and ceramic magnetoresistive read/write head and a method for producing the same.
2. Description of Related Art
Disk drive systems are widely used to store data and software for computer systems. A disk drive system generally includes a disk storage media mounted on a spindle such that the disk can rotate thereby permitting an electromagnetic head mounted on a movable arm to read and write information thereon. Data read/write operations are performed by positioning the head to a selected radial position on the surface of the rotating disk. A head reads or writes data by detecting or creating magnetized regions on the platter coating, respectively.
The electromagnetic head for a disk drive system is usually mounted in a carrier called a xe2x80x9cslider.xe2x80x9d The slider serves to support the head and any electrical connections between the head and the rest of the disk drive system. The slider maintains a uniform distance from the surface of the rotating disk to prevent the head from undesirably contacting the disk. This is accomplished by incorporating aerodynamic features into the slider that causes the slider to glide above the disk surface over the moving air.
Computer users are constantly demanding greater data-storage capacity. Thus, disk drive makers are forever trying to increase the storage capacity of their products. In the process, they are also constantly trying to minimize the actual, physical size of those drives. The accomplishment of these goals requires both shrinking the spacing of the tracks so that more data can fit on a disk squeezing bits more closely together on the tracks, and reducing the distance between the head and disk. Thus, disk drive manufacturers must develop heads that record narrower tracks and fly at a reduced spacing.
In regards to the reduced spacing, the magnetic field pattern around the gap in the head spreads and weakens very rapidly with distance away from the gap. Because the relevant distance is from the gap to the magnetizable platter coating, the design must include both the air gap (the actual height at which the head flies above the upper surface of the platter) and the thickness of any protective or lubricating overcoating that may have been applied to the platter or head. Thus, disk drive manufacturers must develop ways of minimizing the height at which the head flies above the disk surface while providing cost effective manufacturing techniques.
Typically, a magnetic head may be disposed on a titanium carbide ceramic slider body. On the trailing edge of the magnetic head a magnetic sensor is formed on the edge. This surface is coated with alumina insulator followed by a permalloy shield made of nickel and iron. Each of the critical elements of a magnetic head becomes more susceptible to destruction by electrostatic discharge as the dimensions are reduced. Nevertheless, any electrostatic discharge protection may be common to a variety of magnetic head designs.
One method of providing additional circuitry, such as electrostatic discharge protection circuits, to a magnetic head assembly is by combining a magnetic head assembly with a silicon chip. In this manner, the slider/head design may be selected independently of the type of silicon chip that provides additional circuitry. However, providing additional circuitry via the silicon chip adds space to the limited area on a head. Accordingly, disk drive manufacturers must search for ways to improve the fabrication of magnetic heads. In addition, the possibility of having a head that has a flexible/deformable layer can introduce the ability of the head to decrease the fly height of the head.
Thus, it can be seen that there is a need for an enhanced silicon and ceramic magnetoresistive read/write head and a method for producing the same.
To overcome the limitations in the prior art described above, and to overcome other limitations that will become apparent upon reading and understanding the present specification, the present invention discloses an enhanced silicon and ceramic magnetoresistive read/write head and a method for producing the same.
The present invention solves the above-described problems by providing a using a low temperature ( less than 200xc2x0 C.) epoxy or polymethyl methracrylate (PMMA) bonding to provide slider length repeatability, maintain the gram load of the head and minimize alteration in the finished head. An etch stop material is deposited or a sacrificial layer is embedded in the silicon chip to allow precise removal of unwanted silicon to ensure the silicon wafer thickness does not add to the length of the ABS or to the gram load of the slider. A deformable layer or device is deposited adjacent the silicon wafer to allow a higher average fly height while providing near contact reading and writing when the layer or device is deformed.
A method in accordance with the principles of the present invention includes providing a silicon wafer which has a pair of oppositely facing substantially flat faces, fabricating one or more devices on the silicon wafer, etching at least one trench in the silicon in a first of the oppositely facing substantially flat faces, depositing a hard, polishing-resistant material in the at least one trench to form at least one etch stop, polishing the silicon wafer from a second of the oppositely facing substantially flat faces until an etch stop is encountered and coupling the first of the oppositely facing substantially flat faces of the silicon wafer to a slider body.
Other embodiments of a method in accordance with the principles of the invention may include alternative or optional additional aspects. One such aspect of the present invention is that the coupling further comprises bonding the silicon wafer to the slider body using a low temperature bonding material.
Another aspect of the present invention is that the bonding material is spun on the silicon wafer or the slider body.
Another aspect of the present invention is that the bonding material comprises an epoxy.
Another aspect of the present invention is that the bonding material comprises polymethyl methracrylate.
Another aspect of the present invention is that the silicon circuit device comprises an electrostatic discharge protection device.
Another aspect of the present invention is that the silicon circuit device comprises an a magneto-resistive element.
Another aspect of the present invention is that the hard, polish-resistant material comprises tungsten.
Another aspect of the present invention is that the hard, polish-resistant material comprises tantalum.
Another aspect of the present invention is that the method further includes probing at least one etch stop to determined the amount of silicon that has been removed and continuing to polish the silicon wafer until a predetermined amount of silicon has been removed.
Another aspect of the present invention is that the method further includes probing at least one etch stop to determined the resistance of at least one etch stop and continuing to polish the silicon wafer until the at least one etch stop has a predetermined resistance or thickness.
Another aspect of the present invention is that the method further includes forming a deformable layer over the first of the oppositely facing substantially flat faces of the silicon wafer prior to bonding.
Another aspect of the present invention is that the deformable layer is selectably excitable to cause the deformable layer to deform, the expansion torqueing the silicon wafer and silicon circuit devices toward a disk surface.
Another aspect of the present invention is that the deformable layer provides a high average fly height for the head and reduces the fly height to near contact when an electromagnetic device is activated.
Another embodiment of the present invention includes an enhanced silicon and ceramic magnetoresistive read/write head, the head including a silicon wafer having a pair of oppositely facing substantially flat faces and one or more devices on the silicon wafer, at least one etch stop imbedded in a first of the oppositely facing substantially flat faces of the silicon wafer for determining the thickness of the silicon wafer and a slider body coupled to a second of the oppositely facing substantially flat faces the silicon wafer.
Another embodiment of the present invention includes a disk drive system, the disk drive including a magnetic storage disk for storing data thereon, a MR head located proximate to the disk for reading and writing data to and from the disk, a disk movement device, coupled to the disk, for rotating the disk, an actuator arm, coupled to the MR head, for supporting the MR head and an actuator, coupled to the access arm, for moving actuator arm to position the MR head relative to the disk; wherein the MR head further includes a silicon wafer having a pair of oppositely facing substantially flat faces and one or more devices on the silicon wafer, at least one etch stop imbedded in a first of the oppositely facing substantially flat faces of the silicon wafer for determining the thickness of the silicon wafer and a slider body coupled to a second of the oppositely facing substantially flat faces to the silicon wafer.
These and various other advantages and features of novelty which characterize the invention are pointed out with particularity in the claims annexed hereto and form a part hereof. However, for a better understanding of the invention, its advantages, and the objects obtained by its use, reference should be made to the drawings which form a further part hereof, and to accompanying descriptive matter, in which there are illustrated and described specific examples of an apparatus in accordance with the invention.